Embodiments of the invention relate to the field of data storage, and in particular, to providing configuration options for optimizing storage extent placement in multi-tiered storage systems.
Enterprise storage systems seek to provide performance and reliability at minimum capital and operating cost using high performance hard disk drives (HDDs). However, Solid-state drives (SSDs) offer a high random access capability per gigabyte (GB) ratio and have had reductions in cost, and therefore have become more affordable and suitable for enterprise storage. Storage systems with only SSDs are still too expensive and storage systems with only HDDs cannot provide cost-effective performance for most enterprise computing workloads.
Storage tiering is a type of storage architecture that assigns different categories of data to different types of storage media. Storage tiering aims to reduce storage costs to an IT infrastructure, while meeting performance requirements. Tiering categories are primarily based on performance requirements, frequency of use, and levels of protection needed. For example, multi-tier storage systems may contain a mix of storage device types. SSDs may be used for one of the storage tiers to provide high performance storage and specific types of HDDs at a lower cost than SSD may be used for other tiers that do not require high performance to meet customer storage requirements.
Current commercial SSD-based multi-tier systems (e.g., IBM System Storage™ Easy Tier) include multi-tier capabilities that provide performance gains and cost savings. However, customer adoption has been slow due to the difficulty to determine what mix of devices will perform well at minimum cost in the customer's data center. This determination is highly complex given the number of device types available along with the variability of workloads in the data center. Storage sales teams currently routinely over-provision enterprise storage systems' configuration based on incomplete workload information and conservative performance modeling techniques. As a result, the storage configurations may not meet customer expectations for performance and cost.